From a10fe66c9f32e6dc1795da2f338723a5bfb78d3c Mon Sep 17 00:00:00 2001
From: Yasuo Ohgaki <yohgaki@php.net>
Date: Thu, 7 Apr 2016 16:28:19 +0900
Subject: [PATCH 1/2] Enable session_create_id() function

---
 ext/session/session.c                         |  8 ++-
 .../tests/session_create_id_basic.phpt        | 57 +++++++++++++++++++
 2 files changed, 62 insertions(+), 3 deletions(-)
 create mode 100644 ext/session/tests/session_create_id_basic.phpt

diff --git a/ext/session/session.c b/ext/session/session.c
index eaa18c908f125..acfceafe9f0a2 100644
--- a/ext/session/session.c
+++ b/ext/session/session.c
@@ -2158,7 +2158,6 @@ static PHP_FUNCTION(session_regenerate_id)
 
 /* {{{ proto void session_create_id([string prefix])
    Generate new session ID. Intended for user save handlers. */
-#if 0
 /* This is not used yet */
 static PHP_FUNCTION(session_create_id)
 {
@@ -2195,9 +2194,7 @@ static PHP_FUNCTION(session_create_id)
 	}
 	smart_str_0(&id);
 	RETVAL_NEW_STR(id.s);
-	smart_str_free(&id);
 }
-#endif
 /* }}} */
 
 /* {{{ proto string session_cache_limiter([string new_cache_limiter])
@@ -2468,6 +2465,10 @@ ZEND_BEGIN_ARG_INFO_EX(arginfo_session_id, 0, 0, 0)
 	ZEND_ARG_INFO(0, id)
 ZEND_END_ARG_INFO()
 
+ZEND_BEGIN_ARG_INFO_EX(arginfo_session_create_id, 0, 0, 0)
+	ZEND_ARG_INFO(0, prefix)
+ZEND_END_ARG_INFO()
+
 ZEND_BEGIN_ARG_INFO_EX(arginfo_session_regenerate_id, 0, 0, 0)
 	ZEND_ARG_INFO(0, delete_old_session)
 ZEND_END_ARG_INFO()
@@ -2552,6 +2553,7 @@ static const zend_function_entry session_functions[] = {
 	PHP_FE(session_module_name,       arginfo_session_module_name)
 	PHP_FE(session_save_path,         arginfo_session_save_path)
 	PHP_FE(session_id,                arginfo_session_id)
+	PHP_FE(session_create_id,         arginfo_session_create_id)
 	PHP_FE(session_regenerate_id,     arginfo_session_regenerate_id)
 	PHP_FE(session_decode,            arginfo_session_decode)
 	PHP_FE(session_encode,            arginfo_session_void)
diff --git a/ext/session/tests/session_create_id_basic.phpt b/ext/session/tests/session_create_id_basic.phpt
new file mode 100644
index 0000000000000..490128ee9cea0
--- /dev/null
+++ b/ext/session/tests/session_create_id_basic.phpt
@@ -0,0 +1,57 @@
+--TEST--
+Test session_create_id() function : basic functionality
+--INI--
+session.save_handler=files
+--SKIPIF--
+<?php include('skipif.inc'); ?>
+--FILE--
+<?php
+
+ob_start();
+
+/*
+ * Prototype : string session_create_id([string $prefix])
+ * Description : Create new session ID with prefix optionally.
+ * Source code : ext/session/session.c
+ */
+
+echo "*** Testing session_create_id() : basic functionality ***\n";
+
+// No session
+var_dump(session_create_id());
+var_dump(session_create_id('ABCD'));
+
+ini_set('session.use_strict_mode', true);
+$sid = session_create_id('XYZ');
+var_dump($sid);
+var_dump(session_id($sid));
+session_start();
+var_dump(session_id());
+var_dump(session_id() === $sid);
+session_destroy();
+
+ini_set('session.use_strict_mode', false);
+$sid = session_create_id('XYZ');
+var_dump($sid);
+var_dump(session_id($sid));
+session_start();
+var_dump(session_id());
+var_dump(session_id() === $sid);
+session_destroy();
+
+echo "Done";
+ob_end_flush();
+?>
+--EXPECTF--
+*** Testing session_create_id() : basic functionality ***
+string(32) "%s"
+string(36) "ABCD%s"
+string(35) "XYZ%s"
+string(0) ""
+string(32) "%s"
+bool(false)
+string(35) "XYZ%s"
+string(0) ""
+string(35) "XYZ%s"
+bool(true)
+Done

From f0b9e5a476bff66342322a97f97623ccfc4b760f Mon Sep 17 00:00:00 2001
From: Yasuo Ohgaki <yohgaki@php.net>
Date: Wed, 10 Aug 2016 18:06:39 +0900
Subject: [PATCH 2/2] Add collision detection

---
 ext/session/session.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/ext/session/session.c b/ext/session/session.c
index a7746cb25860a..b05e2a73282cc 100644
--- a/ext/session/session.c
+++ b/ext/session/session.c
@@ -2195,7 +2195,20 @@ static PHP_FUNCTION(session_create_id)
 	}
 
 	if (PS(session_status) == php_session_active) {
-		new_id = PS(mod)->s_create_sid(&PS(mod_data));
+		int limit = 3;
+		while (limit--) {
+			new_id = PS(mod)->s_create_sid(&PS(mod_data));
+			if (!PS(mod)->s_validate_sid) {
+				break;
+			} else {
+				/* Detect collision and retry */
+				if (PS(mod)->s_validate_sid(&PS(mod_data), new_id) == FAILURE) {
+					zend_string_release(new_id);
+					continue;
+				}
+				break;
+			}
+		}
 	} else {
 		new_id = php_session_create_id(NULL);
 	}